What the ENW21423 controls and how it protects
The Schneider Electric ENW21423 is a microprocessor-based control unit for the EasyPact NW range of air circuit breakers. It carries the Trip System 2.0E with LI protection — that's long-time overload and instantaneous short-circuit in one package, covering the standard industrial protection profile. The trip unit rating spans 800 to 4000 A, so it governs the full current range of the breaker frame it sits in, not a single fixed setting. That means the unit is certified for the fault-clearing and coordination requirements of industrial distribution panels, not just residential or light commercial gear.
Setting up the protection curves — what the adjustments mean
Long-time pickup (Ir) is adjustable from 0.4 to 1.0 x In across nine settings, and the long-time delay (Tr) runs 0.5 to 24 seconds at 6 x Ir, with an accuracy tolerance of 0 to -20%. That negative-only tolerance means the actual trip time will be at or faster than the dial setting — a deliberate safety margin so the breaker clears before the cable insulation reaches its limit. Instantaneous pickup (Ii) adjusts from 1.5 to 10 x Ir, also nine settings, with ±10% accuracy. For a line-down scenario, the nine-position dials let you match the existing coordination study without swapping the entire trip unit. That prevents immediate reclose onto a still-hot conductor — useful on motor feeders where repeated starts can overheat the cable before the breaker's thermal model resets.
Fault diagnostics and zone selectivity
The digital display reports internal fault, overload, short-circuit, and earth fault conditions. That's four distinct fault types visible without a separate communication module — speeds up troubleshooting on a downed line. Zone selective interlocking (ZSI) is built in, so multiple breakers in a cascade can coordinate trip timing without adding external relay logic. Neutral protection is configurable: 3D (no neutral protection), 3D + N/2 (half-rated neutral), or 4D (full neutral protection). The neutral position is left-side, matching the EasyPaw NW breaker's standard bus arrangement. Protected poles can be set to 3D, 4D, or 3D + N/2, giving flexibility for delta or wye systems without a hardware change.
Mounting and environment — fixed installation in the panel
Mounting mode is fixed — this trip unit bolts into the breaker cradle, not a draw-out chassis. Dimensions are 200 mm high, 55 mm wide, 75 mm deep. The 55 mm width matches the standard EasyPact NW pole spacing, so it occupies one pole width on the DIN-rail or panel-mount assembly.